Conductor Stress Control – Volume Resistivity Test ( WC 5, ICEA S-61-402 )

This test determines the volume resistivity of the conductor stress control layer in power cables.

Test Method (per standard section 6.9.4.2):
- The sample is cut longitudinally and the conductor is removed.
- Four silver-painted electrodes are applied to the conductor stress control layer.
- Two potential electrodes are placed at least 2 inches (50.8 mm) apart.
- A current electrode is placed at least 1 inch (25.4 mm) beyond each potential electrode.
- If high accuracy is not required, the test may be done with only two electrodes spaced at least 2 inches apart.
- Power shall not exceed 100 milliwatts.
- The test is conducted at the specified temperature, using either AC or DC.

Volume Resistivity Formula:
ρ = R × (D² - d²) / (100 × L)

Where:
ρ = Volume resistivity in ohm-meters
R = Measured resistance in ohms
D = Outer diameter over the stress control layer (in inches)
d = Diameter over the conductor (in inches)
L = Distance between potential electrodes (in inches)

Purpose:
This test ensures that the semi-conductive layer over the conductor meets the required resistivity to properly control electric field stress and prevent insulation breakdown.

Note:
Always verify calibration of electrodes and ensure surface uniformity before measurement for accurate results.